This invention relates to a portable drilling rig, and in particular to a drilling rig of the type which is adapted to be mounted on a truck or similar vehicle.
The prior art discloses many vehicle supported drilling rigs. Such rigs are disclosed, inter alia, by U.S. Pat. Nos. 2,817,495, issued to E. J. Pearl on Dec. 24, 1957; 2,954,210, issued to H. W. Comfort on Sept. 27, 1960; 3,089,550, issued to J. V. Watson on May 14, 1963; 3,144,135, issued to H. D. Brown on Aug. 11, 1964; 3,340,938, issued to J. H. Wilson on Sept. 12, 1967; 3,576,218, issued to E. J. Lesenby on Apr. 27, 1971 and 3,645,343, issued to G. E. Mays on Feb. 29, 1972. Many of the drilling rigs disclosed by such art are large, heavy machines intended for use on level ground. In fact, many of the vehicles or rigs are equipped with levelling devices for ensuring that the rig-supporting structure is maintained in a horizontal plane. It is readily apparent from a review of such art that a need exists for an uncomplicated portable drilling rig which can be used on smooth or rough terrain.
The object of the present invention is to provide a relatively simple portable drilling rig which can be used in drilling operations remote from a carrier vehicle, e.g. roadside drilling in which the vehicle remains on the road and drilling occurs in a ditch or other location at the side of the road.